US5825755A
Expired / Lapsed
US
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Method and apparatus for switching between full-duplex and half-duplex CSMA/CD systems
Assignee: Nortel Networks Ltd
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Filing: 1995-01-19
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Granted: 1998-10-20
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Expires: 2015-01-19
Abstract
Abstract A method and apparatus for a node to automatically switch between half-duplex and full-duplex transmission in CSMA/CD networks characterized by a first and second device coupled over a communication link to allow communication of information and control signals between the first and second device. Each of the two devices include a transmit circuit and a receive circuit, wherein the first device begins to transmit information on a first communication circuit, the first communication circuit providing for communication of information between the first device and the second device, and the second device receives the transmitted information. If, while the first device is transmitting information to the second device, the second device begins to transmit information on a second communication circuit, the second communication circuit providing for communication of information between the second device and the first device, and the first device receives the transmitted information, full-duplex communication therebetween is established. If, while the first device is transmitting information to the second device, the second device transmits a collision detect signal and the first device receives the collision detect signal, half-duplex communication therebetween is subsequently established.
Inventors
- 👤 Geoffrey O. Thompson
- 👤 Paul Woodruff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:18
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/4013; H04L12/40136; H04L12/407; H04L12/413
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
80 words
A method for a first node coupled to a network for switching between a half-duplex and a full-duplex transmission of frames of data in said network, comprising: a) transmitting said frames of data from said first node in full-duplex mode on said network; and b) switching to transmitting said frames of data from said first node in half-duplex mode on said network if a collision transmitted from a second node coupled to said network is detected by said first node.
Claim 2
Independent Claim
80 words
A method for a first node coupled to a network for switching between a half-duplex and a full-duplex transmission of frames of data in said network, comprising: a) transmitting said frames of data from said first node in full-duplex mode on said network; and b) switching to transmitting said frames of data from said first node in half-duplex mode on said network if a collision transmitted from a second node coupled to said network is detected by said first node.
Claim 3
Dependent Claim
14 words
The method recited in claim 1 where said network is a local area network.
Claim 4
Dependent Claim
15 words
The method recited in claim 2 wherein said local area network is a CSMA/CD network.
Claim 5
Dependent Claim
78 words
The method recited in claim 3 wherein a collision detection circuit and a loopback circuit of a media attachment unit in said first node are disabled while said first node is transmitting said frames of data in full-duplex mode on said network, and said collision detection circuit and said loopback circuit of said media attachment unit in said first node are enabled while said first node is transmitting said frames of data in half-duplex mode on said network.
Claim 6
Dependent Claim
14 words
The method recited in claim 3 wherein said CSMA/CD network is a point-to-point network.
Claim 7
Dependent Claim
18 words
The method recited in claim 5 wherein a communication medium of said point-to-point network is twisted pair wires.
Claim 8
Dependent Claim
50 words
The method recited in claim 6 wherein said twisted pair wires comprises two sets of pairs of said twisted pair wires, a first set for providing communication from said first node to said second node and a second set for providing communication from said second node to said first node.
Claim 9
Dependent Claim
16 words
The method recited in claim 6 wherein said twisted pair wires is unshielded twisted pair wires.
Claim 10
Dependent Claim
18 words
The method recited in claim 5 wherein a communication medium of said point-to-point network is fiber optic cable.
Claim 11
Independent Claim
73 words
A method for switching between a half-duplex transmission of data and a full-duplex transmission of said data between a first device and a second device coupled in a network comprising the steps of: a) transmitting said data on said network from said first device in full-duplex mode; b) transmitting a collision from said second device to said first device; and c) switching said first device to half-duplex transmission in response to step b.
Claim 12
Independent Claim
73 words
A method for switching between a half-duplex transmission of data and a full-duplex transmission of said data between a first device and a second device coupled in a network comprising the steps of: a) transmitting said data on said network from said first device in full-duplex mode; b) transmitting a collision from said second device to said first device; and c) switching said first device to half-duplex transmission in response to step b.
Claim 13
Dependent Claim
13 words
The method recited in claim 10 wherein said data is transmitted in frames.
Claim 14
Dependent Claim
14 words
The method recited in claim 10 wherein said network is a local area network.
Claim 15
Dependent Claim
15 words
The method recited in claim 12 wherein said local area network is a point-to-point network.
Claim 16
Independent Claim
88 words
A method for a node coupled to a network for switching from a full-duplex transmission of data on said network to a half-duplex transmission of data on said network comprising the steps of: a) initially transmitting data from said node on said network and receiving data at said node from said network in full-duplex mode; and b) transmitting data from said node on said network and receiving data at said node from said network in half-duplex mode if a collision on said network is detected by said node.
Claim 17
Independent Claim
88 words
A method for a node coupled to a network for switching from a full-duplex transmission of data on said network to a half-duplex transmission of data on said network comprising the steps of: a) initially transmitting data from said node on said network and receiving data at said node from said network in full-duplex mode; and b) transmitting data from said node on said network and receiving data at said node from said network in half-duplex mode if a collision on said network is detected by said node.
Claim 18
Dependent Claim
13 words
The method recited in claim 14 wherein said data is transmitted in frames.
Claim 19
Dependent Claim
14 words
The method recited in claim 14 wherein said network is a local area network.
Claim 20
Dependent Claim
15 words
The method recited in claim 16 wherein said local area network is a point-to-point network.
Claim 21
Dependent Claim
24 words
The method recited in claim 14 wherein said full-duplex transmission of said data generally occurs at a transmission rate of 20 megabits per second.
Claim 22
Dependent Claim
24 words
The method recited in claim 14 wherein said full-duplex transmission of said data generally occurs at a transmission rate of 200 megabits per second.
Claim 23
Dependent Claim
24 words
The method recited in claim 14 wherein said half-duplex transmission of said data generally occurs at a transmission rate of 10 megabits per second.
Claim 24
Dependent Claim
24 words
The method recited in claim 14 wherein said half-duplex transmission of said data generally occurs at a transmission rate of 100 megabits per second.
Claim 25
Independent Claim
129 words
A method for a first node coupled to a network for switching from a full-duplex transmission of frames of data on said network to a half-duplex transmission of frames of data on said network comprising the steps of: a) initializing said first node to transmit and receive frames of data on said network in full-duplex mode; b) transmitting frames of data from said first node on said network; c) concurrently receiving at said first node frames of data transmitted by a second node coupled to said network; and d) switching said first node to transmitting and receiving frames of data on said network in half-duplex mode if a frame is received at said first node from said second node indicating a collision has been detected by said second node.
Claim 26
Independent Claim
129 words
A method for a first node coupled to a network for switching from a full-duplex transmission of frames of data on said network to a half-duplex transmission of frames of data on said network comprising the steps of: a) initializing said first node to transmit and receive frames of data on said network in full-duplex mode; b) transmitting frames of data from said first node on said network; c) concurrently receiving at said first node frames of data transmitted by a second node coupled to said network; and d) switching said first node to transmitting and receiving frames of data on said network in half-duplex mode if a frame is received at said first node from said second node indicating a collision has been detected by said second node.
Claim 27
Dependent Claim
129 words
The method recited in claim 22 wherein step d) comprises the steps of: a) continuing to transmit frames of data from said first node over said network and receive frames of data at said first node from said network in full-duplex if said frame received at said first node from said second node over said network is greater than or equal to a minimum valid frame size for a frame of data, and b) switching to transmitting frames of data from said first node over said network and receiving frames of data at said first node from said network in half-duplex if said frame received at said first node from said second node over said network is less than said minimum valid frame size for said frame of data.
Claim 28
Dependent Claim
171 words
The method recited in claim 22 wherein step d) comprises the steps of: a) continuing to transmit frames of data from said first node to and receive frames of data at said first node from said network in full-duplex if said frame received from said second node over said network is greater than or equal to a minimum valid frame size for said frame of data; b) continuing to transmit frames of data from said first node to and receive frames of data at said first node from said network in full-duplex if said frame received from said second node over said network is less than a minimum valid frame size for a collision; and c) switching said first node to transmit and receive said frames of data on said network in half-duplex if said frame received from said second node over said network is greater than or equal to said minimum valid frame size for said collision and less than said minimum valid frame size for said frames of data.
Claim 29
Dependent Claim
78 words
The method recited in claim 24 wherein step a) comprises the step of: a) switching said first node to transmit and receive frames of data on said network in half-duplex if said frame received from said second node over said network is greater than or equal to said minimum valid frame size for said collision and less than said minimum valid frame size for said frame of data and does not include a valid cyclical redundancy check flag.
Claim 30
Dependent Claim
14 words
The method recited in claim 22 wherein said network is a local area network.
Claim 31
Dependent Claim
15 words
The method recited in claim 26 wherein said local area network is a point-to-point network.
References Cited (Backward Citations)
US4531238A
Cited
US4630288A
Cited
US4759018A
Cited
US4920533A
Cited
US5119372A
Cited
US5012467A
Cited
US5121382A
Cited
US5249183A
Cited
US5504738A
Cited
US5351241A
Cited
US5541964A
Cited
US5432775A
Cited
US5572511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-10-19 | 2002-04-20 | 2002-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-19 | 2006-04-20 | 2006-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-19 | 2010-04-20 | 2010-10-20 | $7700.00 | Window Closed / Lapsed |